Electromigration (EM) is a term used to describe the transport of material caused by the gradual movement of the ions in a conductor due to the momentum transfer between conducting electrons and diffusing metal atoms. This effect is important in applications where high direct current densities are used, such as in microelectronics and related structures. As the structure size in electronics such as integrated circuits (ICs) decreases, the practical significance of this effect increases. If the effects of electromigration are not taken into account when designing the layout of the IC, the lifetime of the circuit may be drastically shortened.
Many different tools have been developed to aid in the design of integrated circuits. One of those tools is capable of reviewing a circuit layout and simulating the amount of current drawn throughout the circuit in order to determine of if the circuit is compliant with a series of EM rules applicable for a given manufacturing process. When IC layouts are large and complex, it becomes time consuming to perform the EM simulation each time a change is made to the elements of the layout.